Now you can blame your potty-mouth on evolution

My mother once told me that my great-grandfather, after his stroke, could not talk, except for cursing. He would curse a blue streak when upset. I concluded from this that cursing must be controlled by a different part of the brain than most other forms of speech.

"Swearing is such a common response to pain that there has to be an underlying reason why we do it," says psychologist Richard Stephens of Keele University in England, who led the study. And indeed, the findings point to one possible benefit: "I would advise people, if they hurt themselves, to swear," he adds.

How swearing achieves its physical effects is unclear, but the researchers speculate that brain circuitry linked to emotion is involved. Earlier studies have shown that unlike normal language, which relies on the outer few millimeters in the left hemisphere of the brain, expletives hinge on evolutionarily ancient structures buried deep inside the right half.